The Republican presidential front-runners used appearances before a conservative Jewish audience Wednesday to criticize President Obama’s foreign policy as weak and confused, while pledging to strengthen the U.S. alliance with Israel should they be elected.

Former Massachusetts governor Mitt Romney told a forum hosted by the Republican Jewish Coalition (RJC) that his first foreign trip as president would be to Israel. A few hours later, former House speaker Newt Gingrich (Ga.) promised to move the U.S. Embassy from Tel Aviv to Jerusalem — claimed by both Israelis and Palestinians as their capital.

Wednesday’s forum represented an explicit challenge to Obama and the traditional Jewish support for Democratic candidates. Republicans believe that there is an opportunity to peel away some of Obama’s Jewish backers, particularly by attacking his policies toward Israel. Obama has argued that he has consistently supported Israel’s security needs and political interests, noting his opposition to the Palestinian bid for statehood at the United Nations this year.

Support for Obama stable

Obama’s poll numbers among Jews have remained stable throughout the fall, hovering above his overall ratings nationally. In the latest Gallup poll, 51 percent of Jews approved of the way Obama is handling his job, and 42 percent disapproved. But those numbers mark the lowest ratings of the president’s term among Jews.

Obama has endorsed a two-state solution to the Israeli-Palestinian conflict and urged the two sides to negotiate an agreement based on Israel’s pre-June 1967 boundaries. Those talks on future borders would include land swaps to accommodate large Jewish settlement blocks built on territory claimed by the Palestinians as part of their future state.

The two-state solution has been a policy goal shared by Obama’s Republican and Democratic predecessors. But neither Romney nor Gingrich mentioned the formula — the creation of a Palestinian state alongside Israel — as the model for a future peace.

“One thing we have heard here is a stepping back from decades of bipartisan consensus on how to achieve peace in the Middle East,” said Jeremy Ben-Ami, president of J Street, a Jewish lobbying group that favors the two-state approach. “The politics around Israel have warped policy to the extent to which you may get a president who no longer thinks that a two-state solution is a good thing.”

Romney and Gingrich offered sharp critiques of Obama’s economic record, but some of their harshest words focused on the administration’s approach toward Israel at a time of growing international concern over Iran’s nuclear program and a changing political landscape across the Arab Middle East.

Romney listed the Middle Eastern nations that Obama has visited — including such U.S. allies as Turkey and Saudi Arabia — before noting that the president has so far skipped Israel.

“In the past three years, Obama has instead chastened Israel,” Romney said.

Romney also said that Obama has been “timid and weak in the face of the existential threat that Israel faces from Iran,” promising, as Obama has, that “Iran’s ayatollahs will not be permitted to obtain nuclear weapons on my watch.”

Obama outreach criticized

Gingrich argued that the conflict with radical Islam is in a very early stage, comparing it to the year 1946 in the long U.S. effort to contain Soviet communism. Obama has made it a priority of his administration to repair relations with the Islamic world.

Regarding Iran, Gingrich said the only policy to pursue is “regime replacement.” He said he would target the country’s gasoline supply in an effort to choke off the government’s support and would fund “every dissident group” working in Iran.

To carry out his foreign policy, Gingrich said he would select former U.N. ambassador John R. Bolton as secretary of state, a post he would use to carry out a fundamental reform of the U.S. diplomatic mission.

“This argument that it is always Israel’s fault — no matter how bad the other side is — has to stop,” Gingrich said to applause.

The Obama White House had to defend one of its ambassadors from that charge, stemming from remarks the diplomat made last week.

The ambassador to Belgium, Howard Gutman, described in a Nov. 30 speech at a conference on anti-Semitism in Europe what he called a new form of anti-Semitism arising from Israel’s policies in the Middle East. He contrasted that with traditional anti-Semitism, which he called “classic bigotry, hatred against those who are different and against minorities generally.”

Romney and Gingrich called on Obama to fire Gutman, but the administration has stood by the ambassador. Gingrich reiterated his position Wednesday in his speech to the RJC.

Gutman, who raised money for Obama in 2008, introduced himself in the Nov. 30 speech as the son of a father who left his Polish home town to join the resistance following Nazi Germany’s invasion, only to be rejected for looking “too Jewish.” When he returned home after a week, the town’s Jewish section “no longer existed,” he told the audience.

Gutman apologized at the start of his talk “for not saying what you would expect me to say.” But, he said, this anti-Semitism “is a serious problem” and “it too must be discussed and solutions explored.”

Gutman identified the “growing intimidation and violence directed at Jews generally as a result of the continuing tensions between Israel and the Palestinian territories and other Arab neighbors in the Middle East.”

Many supporters of Israel, including the RJC, recoiled at the analysis, saying that it blamed necessary Israeli security policies for the hatred against Jews. But within Israel, the military and intelligence agencies have long worried about the effect of Israeli policies on anti-Semitism in Europe, which some organizations have charted as on the rise.

“You can take a line or two out of any speech and blow it up, but there’s no denying that Israel’s policies have an impact on public perception,” Ben-Ami said.

Mike Lachs, an RJC member who traveled from East Brunswick, N.J., for Wednesday’s event, said, “The Republican Party gets that American national security is tied tightly to Israel’s.”

“I think all the candidates here get that too,” he said, noting that he will be voting for Romney.